1. Field of the Invention
The present invention relates to an optical apparatus, an optical element driving unit, and a photographing system used in TV cameras, video cameras, and so on.
2. Related Background Art
A variety of photographing techniques are employed in TV and video photography and one of them is a photographing technique wherein during photography of an object at a certain zoom magnification, the magnification is altered to another zoom magnification, and thereafter the magnification is returned to the original zoom magnification to continue the photography.
For implementing the photographing technique of this type, there are two conventional approaches; a manual method in which an operator remembers a current zoom position, alters the zoom magnification by servo driving or manual driving, and thereafter returns the zoom lens to the original zoom position by servo driving or manual driving; and a method, as illustrated in FIG. 18 and FIG. 19, in which an external device called an external preset box is coupled to a camera or a lens mounted on a tripod or the like and in which the zoom lens is automatically moved between the above two positions through operation of the preset box.
Further, EP0682450A1, Japanese Patent Application Laid-Open No. 11-160604, and Japanese Patent Application Laid-Open No. 11-271592 disclose the technology of moving the zoom lens to the telephoto extreme during photography and thereafter returning the zoom lens to the original position to continue the photography.
In the photography with the tripod or the like, zooming and focusing is controlled through zoom demand 20 and focus demand 21. The aforementioned preset box is often mounted on the zoom demand 20.
As illustrated in FIG. 19, the preset box is provided with switches 22, 23, 24 for initiating zoom movement and volumes 25, 26, 27 for permitting the operator to preset desired zoom positions for zoom movement. The switches and volumes are paired in correspondence with each other, and with depression of either switch, the zoom lens is moved to the zoom position preset by the corresponding volume.
For example, the operator presets two objective zoom positions for photography by the volumes 25, 26 and first depresses the switch 1 to move the zoom lens to one preset position and photograph the object. Thereafter, the operator depresses the switch 2 to move the zoom lens to the other preset position and photograph the object at another magnification. Further, the operator depresses the switch 1 to return the magnification to the original zoom magnification and photograph the object thereat.
In practical photography, however, the operator needs to be considerably skilled in the method in which the operator first remembers the original zoom position and then manually returns the lens to the original position, and it is not always assured that the operator, even if well skilled, can reproduce exactly the same original zoom position.
Reproducibility can be improved by use of the preset box, but the box tends to become large, because it necessitates at least two volumes and two switches. This degrades the carryability of the camera system and the large box has to be always kept at hand. Namely, this system can be used with few problems in cases where the camera and lens can be fixed on the tripod or the like in photography at a studio or the like, because the operator can keep the box at hand. On the other hand, in cases where the system is used for outdoor photography without use of the tripod or the like, it is considerably difficult to use the system in practice, because there is no way of mounting this box.
Further, with use of the preset box, for example, when the operator desires to set the current zoom position as one preset position, it is difficult for the operator to accurately match the control position of the volume with the current zoom position perceived through a viewer mounted on the TV camera or through the viewfinder of the video camera. As a result, it poses another problem that high reproducibility is not achieved in many cases.
In the case of the method disclosed in aforementioned EP0682450A1, Japanese Patent Application Laid-Open No. 11-160604, and Japanese Patent Application Laid-Open No. 11-271592, there arises a problem that the zoom lens cannot be moved to any other position than the telephoto extreme.
An object of the present invention is, therefore, to provide an optical apparatus, an optical element driving unit, and a photographing system with good carryability and operability, which permit the movement of the lens unit to an arbitrary preset position and the return operation to the original position with high reproducibility.
For accomplishing the above object, a first aspect of the present invention is an optical apparatus comprising:
operation means for permitting a first operation and a second operation;
position detecting means for detecting a position of an optical element;
target position setting means for permitting arbitrary setting of a target position in driving of the optical element; and
control means for controlling the driving of the optical element,
wherein the control means stores the position of the optical element detected by the position detecting means and drives the optical element to the target position set by the target position setting means, in response to the first operation of the operation means, and the control means drives the optical element to the stored position of the optical element detected by the position detecting means, in response to the second operation of the operation means.
In a more preferable aspect, the second operation is release of the first operation.
In a more preferable aspect, when the control means drives the optical element to the target position set by the target position setting means, in response to the first operation, and when the target position is changed to another target position by the target position setting means without execution of the second operation, the control means drives the optical element to the target position after the change.
In a more preferable aspect, the optical element is a lens unit having zooming action.
In a more preferable aspect, the optical apparatus comprises a lens unit having focusing action, in addition to the lens unit having the zooming action, and the lens unit having the zooming action is located at a position closer to the image plane than the lens unit having the focusing action.
In a more preferable aspect, the optical apparatus comprises a lens unit having focusing action, in addition to the lens unit having the zooming action, and the lens unit having the focusing action is located at a position closer to the image plane than the lens unit having the zooming action.
In a more preferable aspect, the optical apparatus comprises: a lens unit having focusing action, in addition to the lens unit having the zooming action; and focusing lens position detecting means for detecting a position of the lens unit having the focusing action; and the control means stores the position of the lens unit having the focusing action, detected by the focusing lens position detecting means, and drives the lens unit having the focusing action to a position where an in-focus state is achieved with respect to the lens unit having the zooming action, driven to the target position, in response to the first operation, and the control means drives the lens unit having the focusing action to the stored position of the lens unit having the focusing action, detected by the focusing lens position detecting means, in response to the second operation.
In a more preferable aspect, the control means calculates a position of the lens unit having the focusing action where the in-focus state is achieved, in response to the first operation, and drives the lens unit having the focusing action to the position thus calculated.
In a more preferable aspect, the optical apparatus comprises focus detecting means for detecting a focus state, and, in response to the first operation, the control means drives the lens unit having the focusing action until the focus detecting means detects the in-focus state.
In a more preferable aspect, the target position setting means comprises a volume for variably outputting an electric signal corresponding to the target position of the optical element.
In a more preferable aspect, the target position setting means can set the target position of the optical element on a stepless basis.
In a more preferable aspect, the target position setting means can set the target position of the optical element on a stepwise basis.
In a more preferable aspect, the target position setting means comprises an on/off switch; and when the switch is switched on, the target position setting means sets a position of the optical element detected at the time of on by the position detecting means, as the target position.
In a more preferable aspect, the target position setting means comprises a plurality of on/off switches; and when the plurality of switches all are switched on, the target position setting means sets a position of the optical element detected at the time of on by the position detecting means, as the target position.
In a more preferable aspect, when the target position setting means is switched on and when the first operation is performed, the target position setting means sets a position of the optical element detected at this time by the position detecting means, as the target position.
In a more preferable aspect, when the on operation of the target position setting means and the first operation are carried out simultaneously, the target position setting means sets a position of the optical element detected at this time by the position detecting means, as the target position.
In a more preferable aspect, the optical apparatus comprises a control unit provided with an operation member for control in order to give a command of a driving direction, a driving amount, a driving position, a driving speed, or the like of the optical element; and the operation means and the target position setting means are mounted on the control unit.
In a more preferable aspect, the optical apparatus comprises an operation member for control in order to give a command of a driving direction, a driving amount, a driving position, a driving speed, or the like of the optical element; and when the operation member for control is operated after execution of the second operation and before arrival of the optical element at the position stored in response to the first operation, the control means stores a position of the optical element at the time of completion of the operation of the operation member for control, in place of the position stored in response to the first operation.
In a more preferable aspect, the control means comprises a switch for starting the driving of the optical element.
In a more preferable aspect, the position detecting means outputs an electric signal according to a current position of the optical element.
In a more preferable aspect, the control means comprises an electric circuit.
In a more preferable aspect, the control means comprises a CPU.
In a more preferable aspect, the optical apparatus is a lens apparatus comprising a lens unit having zooming action, a lens unit having focusing action, and a stop.
For accomplishing the above object, a second aspect of the present invention is an optical element driving unit, mounted on or connected to an optical apparatus body, for driving and controlling an optical element in the optical apparatus body, the optical element driving unit comprising:
operation means for permitting a first operation and a second operation;
position detecting means for detecting a position of the optical element;
target position setting means for permitting arbitrary setting of a target position in driving of the optical element; and
control means for controlling the driving of the optical element,
wherein the control means stores the position of the optical element detected by the position detecting means and drives the optical element to the target position set by the target position setting means, in response to the first operation of the operation means, and the control means drives the optical element to the stored position of the optical element detected by the position detecting means, in response to the second operation of the operation means.
In a more preferable aspect, the second operation is release of the first operation.
In a more preferable aspect, when the control means drives the optical element to the target position set by the target position setting means, in response to the first operation, and when the target position is changed to another target position by the target position setting means without execution of the second operation, the control means drives the optical element to the target position after the change.
In a more preferable aspect, the optical element is a lens unit having zooming action, and the control means drives the lens unit having the zooming action in the optical apparatus body.
In a more preferable aspect, the optical element driving unit comprises focusing lens position detecting means for detecting a position of a lens unit having focusing action in the optical apparatus; and the control means stores the position of the lens unit having the focusing action, detected by the focusing lens position detecting means and drives the lens unit having the focusing action to a position where an in-focus state is achieved with respect to the lens unit having the zooming action, driven to the target position, in response to the first operation, and the control means drives the lens unit having the focusing action to the stored position of the lens unit having the focusing action, detected by the focusing lens position detecting means, in response to the second operation.
In a more preferable aspect, the target position setting means comprises a volume for variably outputting an electric signal corresponding to the target position of the optical element.
In a more preferable aspect, the target position setting means comprises an on/off switch; and when the switch is switched on, the target position setting means sets a position of the optical element detected at the time of on by the position detecting means, as the target position.
In a more preferable aspect, the optical element driving unit comprises an operation member for control in order to give a command of a driving direction, a driving amount, a driving position, a driving speed, or the like of the optical element; and when the operation member for control is operated after execution of the second operation and before arrival of the optical element at the position stored in response to the first operation, the control means stores a position of the optical element at the time of completion of the operation of the operation member for control, in place of the position stored in response to the first operation.
In a more preferable aspect, the optical element driving unit is a lens driving unit for driving a lens unit having zooming action, a lens unit having focusing action, and so on.
For accomplishing the above object, a third aspect of the present invention is a photographing system comprising an optical apparatus, the photographing system comprising:
operation means for permitting a first operation and a second operation;
position detecting means for detecting a position of an optical element;
target position setting means for permitting arbitrary setting of a target position in driving of the optical element;
control means for controlling the driving of the optical element; and
photoelectric conversion means for converting light from an optical system of the optical apparatus to an electric signal,
wherein the control means stores the position of the optical element detected by the position detecting means and drives the optical element to the target position set by the target position setting means, in response to the first operation of the operation means, and the control means drives the optical element to the stored position of the optical element detected by the position detecting means, in response to the second operation of the operation means.
In a more preferable aspect, the second operation is release of the first operation.
In a more preferable aspect, when the control means drives the optical element to the target position set by the target position setting means, in response to the first operation, and when the target position is changed to another target position by the target position setting means without execution of the second operation, the control means drives the optical element to the target position after the change.
In a more preferable aspect, the optical element is a lens unit having zooming action, and the control means drives the lens unit having the zooming action in the optical apparatus.
In a more preferable aspect, the photographing system comprises focusing lens position detecting means for detecting a position of a lens unit having focusing action in the optical apparatus; and the control means stores the position of the lens unit having the focusing action, detected by the focusing lens position detecting means, and drives the lens unit having the focusing action to a position where an in-focus state is achieved with respect to the lens unit having the zooming action, driven to the target position, in response to the first operation, and the control means drives the lens unit having the focusing action to the stored position of the lens unit having the focusing action, detected by the focusing lens position detecting means, in response to the second operation.
In a more preferable aspect, the target position setting means comprises a volume for variably outputting an electric signal corresponding to the target position of the optical element.
In a more preferable aspect, the target position setting means comprises an on/off switch and when the switch is switched on, the target position setting means sets a position of the optical element detected at the time of on by the position detecting means, as the target position.
In a more preferable aspect, the photographing system comprises an operation member for control in order to give a command of a driving direction, a driving amount, a driving position, a driving speed, or the like of the optical element; and when the operation member for control is operated after execution of the second operation and before arrival of the optical element at the position stored in response to the first operation, the control means stores a position of the optical element at the time of completion of the operation of the operation member for control, in place of the position stored in response to the first operation.